Screen stencilling machine



Jan. 23, I962 Filed March 30, 1959 H. R. FARWELL 3,017,823 SCREENSTENCILLING MACHINE 4 Sheets-Sheet 1 I INVENTOR zwwellfavwe ll Hang BYfiled 01,3026

ATTORNEY Jan. 23, 1962 H. R. FARWELL 3,017,823

SCREEN STENCILLING MACHINE Filed March so, 1959 4 Sheets-Sheet 2 BYfiuwwmf ATTORNEY Jan, 23,1962- H. R. FARWELL.

SCREEN STENCILLING MACHINE Filed March 30, 1959 4 Sheets-Sheet 3ATTORNEY Jan. 23, 1962 H. R. FARWELL 3,017,823

SCREEN STENCILLING MACHINE Filed March so, 1959 4 Sheets-Sheef 4INVENTOR Hat-g Rad-yell Farulell United States Patent 3,017,823 SCREENSTENCIILLING MAQHINE Harry Russell Farwell, Grand Rapids, Mich, assignorto James A. Black, Grand Rapids, Mich. Filed Mar. 30, 1959, Ser. No.802,916 11 Claims. (1. 101-123) The present invention relates to screenstencilling machines.

The primary objects of the invention are to provide an improved screenstencilling machine of the same general type as the machines disclosedin co-pending applications Serial No. 748,188 and Serial No. 748,360,both filed on July 14, 1958 by the assignee of this application, JamesA. Black; to provide such a machine which, with the appli cation theretoof appropriate jigs, fixtures or conveyor mechanisms, is adaptable forthe semi-automatic silk screening onto a wide variety of articlesincluding flat stock and irregularly shaped stock, and which may even beadapted for the continuous repetition of an impression on tape, ribbonor the like; to provide such a machine in which the movements of thevarious moving parts are automatically timed and co-ordinated; toprovide a novel silk screen mounting frame for such a machine; and ingeneral to provide such a screen stencilling machine which is eflicientin operation, reasonably economical in manufacture, and attractive inappearance.

A11 illustrative embodiment of the invention is shown in theaccompanying drawings, wherein:

FIGURE 1 is a top plan view of the machine with a portion of astock-centering fixture mounted on the machine broken away to betterreveal the stencil and stencil frame of the machine;

FIGURE 2 is a vertical sectional view of the machine taken on lines 2-2of FIGURES l and 3;

FIGURE 3 is a vertical sectional view thereof taken on line 3-3 ofFIGURE 2;

FIGURE 4 is a vertical sectional view of parts of the machine taken online 4-4 of FIGURE 3, and having an electric circuit superimposedthereon diagrammatically;

FIGURE 5 is a vertical sectional view of the machine similar to FIGURE 2but showing certain movable parts thereof in different positions; and

FIGURE 6 is a fragmentary vertical sectional view similar to FIGURES 2and 5 and showing the movable parts thereof in still other positions.

Referring now in detail to these drawings, the machine comprises anupwardly opening box 10 mounted on a base 11 having supporting feet 12and the box 10 comprises a bottom 13, parallel vertical side walls 14,15 and parallel vertical end walls 16, 17. A cover or top It; is securedto the top of the box 10 by means of screws 19 passing through flanges20, 21 extending outwardly from the upper ends of the end walls 16, 17of the box and into the top 18. The top 18 provides a work-supportingupper surface, and it has a rectangular opening 22 therethrough which isin registry with the open upper end of the box 10 and which opening isadapted to receive the screen stencil and its frame.

The rectangular stencil frame 23 comprises four straight strips ofupwardly opening channel stock mitered to fit at the corners and securedtogether as by welding. The frame thus presents a continuous upwardlyopening channel 24. The stencil 25, which may be of silk or fine meshwire, is stretched taut over the top of the stencil frame 23 and issecured to the frame by means of cording 26 which is pressed into thechannel 24 with the marginal edges of the stencil 25 clamped in thechannel. The stencil is thus readily applied to the frame and can bequickly removed therefrom whenever 3,617,823 Patented Jan. 23, 1962 itis desired to replace it with a different stencil. The stencil 25 andits frame 23 are removably mounted in the opening 22 in the top 18 bymeans of a central locating screw 27 threaded in the top 18 at one endof the opening 22, and a pair of bullet catches 28 in the top at theother end of said opening. The screw 27 and bullet catches 28 enterapertures in the outer flanges of the stencil frame 23. When so mounted,the stencil frame 23 rests on the upper edges of the box 10.

A rock shaft 29 has its opposite ends journalled in the lower middleregions of the side walls 14, 15 of the box It). A pair of rocker arms30, 31 are fixedly mounted on the rock shaft 29 and extend upwardlytherefrom adjacent the opposite side walls of the box. The rocker armshave longitudinally extending slots 32, 33 at their upper ends. A pairof tracks 34, 35 are pivotally connected at 36, 37 to the opposite sidewalls 14, 15 respectively of the box 10, between the rocker arms andsaid side walls. The squeegee assembly extends transversely across thebox 10 beneath the screen stencil 25 and comprises a shaft 38, asqueegee holder 39 fixedly mounted on the shaft 38, a rubber squeegeeblade 40 seated in a slot in the holder 39, and a pair of elongatedslides 41, 42 fixedly mounted at the opposite ends of the shaft 38 andslidably disposed on the tracks 34, 35 respectively.

A camshaft 43 has its opposite ends journalled in the opposite sidewalls 14', 15 of the box 10 beneath the pivoted tracks 34, 35 and aboveand to the right of the rock shaft 29 as seen in FIGURES 2, 5 and 6. Thecamshaft 43 carries a pair of identical elevator cams 44, 45 and also apair of identical rocker earns '46, 47, all fixedly mounted on thecamshaft 43 and rotatable therewith. A pair of elevator cam followers48, 49 is rotatably mounted on the lower ends of arms 50, 51 dependinglysecured to the tracks 34, 35 respectively, and these elevator camfollowers bear against the upper surfaces of the elevator cams 44, 45. Apair of rocker cam followers 52, 53 is rotatably mounted on the rockerarms 30, 31 and bear against the outer surfaces of the rocker cams 46,47.

A paint tray 54 is removably mounted within the box 10 and beneath thesqueegee assembly and is a reservoir for the coating material used inthe screening process. The tray 54 has a pair of depending brackets 55which are secured between nuts 56, 57 secured on bolts 58 extendingthrough the end wall 17 of the box 10. The other end of the paint trayrests on studs 59 secured by nuts 60, 61 to the opposite end walls 16 ofthe box 10. A pair of bearing brackets 62, 63 is secured as by weldingto the opposite side walls of the tray 54. A paint distributor 64 has ashaft 65 extending transversely of the paint tray and journalled at itsopposite ends in the bearing brackets 62, 63 for rocking movement. Thisdistributor 64 has oppositely extending longitudinal arms 66, 67 and atransverse distributing arm 68 mounted at the extremity of thelongitudinal arm 66 seen at the left in FIGURES 2, 5 and 6.

Springs 69, 70 are each connected at one end to one of the rocker arms30, 31 and at the other end to eyelet screws 71, 72 secured to the endwall 17 of the box 10 by means of nuts 73. These springs normally urgethe rocker arms 30, 31 toward the right as viewed in FIG- URES 2, 5 and6.

Driving means, best seen in FIGURES 3 and 4, are provided for drivingthe camshaft 43 and thus actuating the various moving parts of themachine. These means comprise an electric motor 74 mounted on the base11, the shaft 75 of which motor carries a worm 76 meshing with a wormgear 77 on a shaft 78 extending through an enclosing gear box 79 alsomounted on the machhies base 11 as here shown. Exteriorly of the gearb0x 79, the shaft 78 carries a gear 80 which meshes with a gear 81 onthe camshaft 43 exteriorly of the box 10. A cam 82 on the camshaft 43,automatically operates a microswitch 83, the function of which isdescribed hereinafter.

A locating fixture generally designated 84 is shown in FIGURES 1, 2 and3 and is secured to the top 18 by means of machine screws 85 passingthrough slots 86 in the top 18 (see FIGURES 1 and 2). This fixture isuniversally adjustable so as to receive practically any type of jigconstructed so as to properly locate the particular type of stock beingprinted, and in proper registry with the screen stencil. Such a jig,designated 87 is provided for locating the cylindrical objects 88 shownin the drawings. A plate 89 is here shown secured to the underside ofthe jig 87 for supporting the marginal edges of the objects 88 whilethey are being printed. Almost any type of jig, fixture or conveyor maybe secured to the upper work-supporting surface of the machine,depending upon the character of the stock to be run. Hence the fixtureshown in FIGURES 1, 2 and 3 is not described in detail herein.

Operation Stock to be printed, such as the cylindrical objects 88 shownin the drawings, is placed one object at a time in the jig 87 forscreening of any kind of design or legend thereon such as company nameand insignia, instructions, and trade marks like that shown in FIGURE 1.An electric switch 90 shown diagrammatically in FIGURE 4, which may beeither manually or pedally operated, is then momentarily closed thusclosing a circuit from a suitable source of electricity indicated bywires 91, 92, through wires 91, 92, 93 and 94 to the electric motor 74,thus energizing the motor to drive camshaft 43 clockwise and start theprint stroke of the machine. When the high point 95 of cam 82 reachesthe microswitch 83, this switch is closed thus automatioaliy maintaininga closed circuit through the motor, through the microswitch 83 andthrough wires 91, 94, 96, 97 and 92, and this circuit remains closeduntil the print stroke of the machineto the left as seen in FIGURES 2,and 6is completed. During this print stroke, elevator earns 44, 45maintain tracks 34, 35 in elevated positions thus pressing the squeegeeblade 40 into contact with the screen stencil and forcing coatingmaterial upwardly through the stencil and onto the stock. The rockercams 46, 47 move the rocker arms 30, 31 and the squeegee assembly to theleft during this print stroke, and in this movement the squeegeeassembly depresses the longitudinal arm 66 of the rocking paintdistributor 64 so that the transverse distributing arm 68 thereof isimmersed in the coating material in the paint tray 54, as seen in FIGURE5.

Upon the completion of the print stroke, cam 82 opens the microswitch 83and the electric circuit through the motor 74, thus de-energizing themotor. Springs 69, 70 then take over and return the rocker arms 30, 31and the squeegee assembly to their starting positions, effecting thenon-print stroke of the machine with a quick snap-action. During thismovement, elevator cams 44, 45 lower tracks 34, as seen in FIGURE 5 thuslowering the squeegee blade out of contact with the screen stencil 25,and the squeegee assembly is returned to its starting position by rockerarms 30, 31, the assembly at this time moving along the upper side edgesof the paint tray 54 on bronze bearings 98, 99 secured on the squeegeesshaft 38 (see FIGURE 3). Tracks 34 and 35 are slowly raised to theirstarting positions by elevator cams 44, during this returning movement.Also during this returning, non-print stroke of the machine, thesqueegee assembly strikes the longitudinal arm 67 of the paintdistributor 64, thus quickly flipping the distributor to its startingposition and splashing coating material across the underside of thescreen stencil 25 in preparation for the next print stroke of themachine.

Having thus described the construction and operation of one preferredembodiment of my invention, I desire to secure by Letters Patent thatembodiment and all such modifications thereof as fall within the spiritof the invention and the scope of the following claims.

I claim:

1. In a screen stencilling machine: upwardly extending substantiallyparallel side walls; a top mounted at the upper ends of the side wallsand having a stock-supporting upper surface and an opening therethroughin registry with the opening between said side walls; a screen stencilmounted in the opening in said top; a pair of tracks pivotally mountedon said side walls respectively near corresponding ends thereof; and asqueegee assembly extending transversely between said side walls andhaving elements at its opposite ends reciprocable longitudinally on saidtracks to effect print and non-print strokes of the squeegee beneathsaid stencil, said tracks being swingable about their pivotal mountingson the side Walls to elevated positions wherein the squeegee forcescoating material upwardly through the stencil and onto stock placed onthe stock-supporting upper surface of the top during the squee-geesprint strokes, and said tracks being swingable to lowered positionswherein the squeegee is lowered out of contact with the stencil duringthe squeegees non-print strokes.

2. A screen stencilling machine according to claim 1 characterized byhaving a camshaft extending transversely between the side walls beneathsaid pivoted tracks, a pair of identical elevator cams on said camshaft,and a pair of elevator cam followers on said tracks bearing against saidelevator cams whereby rotation of the camshaft raises and lowers saidtracks in unison.

3. In a screen stencilling machine: upwardly extending substantiallyparallel side walls; a top mounted at the upper ends of the side wallsand having a stock-supporting upper surface and an opening therethroughin registry with the opening between said side walls; a screen stencilmounted in the opening in said top; a rock shaft having its oppositeends journalled in the lower middle regions of said side walls; a pairof rocker arms mounted on the rock shaft and extending upwardlytherefrom adjacent the side walls respectively; a squeegee assemblyextending transversely between the upper ends of the rocker arms andreciprocable therewith beneath the stencil to effect print strokes andreturning non-print strokes; and means for elevating the squeegee intocontact with I the stencil to force coating material upwardly throughthe stencil and onto stock placed on the stock-supporting upper surfaceof the top, said means also operating to lower the squeegee out ofcontact with the stencil during said returning non-print strokes.

4. A screen stencil machine according to claim 3 characterized by havinga camshaft extending transversely between the side walls, a pair ofidentical rocker cams on said camshaft, and a pair of rocker camfollowers on said rocker arms bearing against said rocker cams wherebyrotation of the camshaft moves the rocker arms in unison in the printstroke direction.

5. A screen stencil machine according to claim 4 including spring meansfor moving the rocker arms in unison through their returning non-printstrokes.

6. In a screen stencilling machine: an upwardly opening box; a topmounted on the box and having a stocksupporting upper surface and anopening therethrough in registry with the open upper end of the box; ascreen stencil mounted in the opening in said top; a squeegee mounted inthe box for reciprocating movements beneath the stencil to effect printstrokes wherein coating material is forced upwardly through the stenciland onto stock placed on the stock-supporting surface of the top, andreturning non-print strokes; a tray disposed in the box beneath thesqueegee for containing the coating material; and a distributor mountedin the tray for rocking movement and having oppositely extendinglongitudinal arms and a transverse distributing arm at the extremity ofone longitudinal arm, the squeegee being adapted to contact saidlongitudinal arms alternately during its reciprocating movements to rockthe distributor so that during the print stroke the distributing arm islowered into the coating material in the tray, and during the non-printstroke the distributing arm is flipped upwardly to splash coatingmaterial onto the underside of the stencil.

7. A screen stencilling machine according to claim 6 in which springmeans are provided for rapidly moving the squeegee through its non-printstroke to that the distributing arm is flipped quickly upwardly.

8. In a screen stencilling machine: an upwardly opening box having abottom, end walls, and substantially parallel side walls; a top mountedon the box and having a stock-supporting upper surface and an openingtherethrough in registry with the open upper end of the box; a screenstencil mounted in the opening in said top; a rock shaft having itsopposite ends journalled in the lower middle regions of said side walls;a pair of rocker arms mounted on the rock shaft and extending upwardlytherefrom adjacent the opposite side walls of the box, said rocker armshaving longitudinally extending slots at their upper ends; a pair oftracks pivotally mounted on said opposite side walls near one end of the'box; and a squeegee assembly extending transversely in the box beneaththe stencil and having slides at its opposite ends movablelongitudinally on said tracks, said squeegee assembly having also pinsextending into the slots in said rocker arms whereby reciprocation ofthe rocker arms reciprocates the squeegee beneath the stencil to effectprint and non-print strokes, said tracks being swingable about theirpivotal mountings on the side walls to elevated positions wherein thesqueegee forces coating material upwardly through the stencil and ontostock placed on the stock-supporting upper surface of the top during thesqueegees print stroke, and said tracks being swingable to loweredpositions wherein the squeegee is lowered out of contact with thestencil during the squeegees nonprint strokes.

9. A screen stencilling machine according to claim 8 characterized byhaving a camshaft extending transversely between the side walls of thebox beneath said pivoted tracks, a pair of identical elevator cams andanother pair of identical rocker cams all mounted on said camshaft, apair of elevator cam followers on said tracks bearing against saidelevator cams and a pair of rocker cam followers on said rocker armsbearing against said rocker cams, whereby rotation of the camshaftraises the tracks so that the squeegee is elevated into contact with thestencil and then moves the rocker arms and the squeegee in the printstroke direction and whereby the squeegee is lowered out of contact withthe stencil at the end of the print stroke.

10. A screen stencilling machine according to claim 9 including springmeans for rapidly returning the rocker arm and squeegee through theirnon-print strokes.

11. A screen stencilling machine according to claim 10 in whichrevolving movement of the camshaft is efiected by an electric motorincluded in a circuit which also includes a switch for starting themotor and means for automatically stopping the motor upon the completionof the print stroke.

References Cited in the file of this patent UNITED STATES PATENTS758,798 Tripp May 3, 1904 1,490,400 Owens Apr. 15, 1924 1,508,116 NantusSept. 9, 1924 1,556,998 Katcher Oct. 13, 1925 1,861,610 Respess June 7,1932 2,039,909 Kern et al. May 5, 1936 2,545,277 Hannah et al Mar. 13,1951 2,606,492 Black Aug. 12, 1952 2,613,596 Meissner Oct. 14, 1952

